From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- arch/arm64/include/asm/mte.h | 219 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 219 insertions(+) create mode 100644 arch/arm64/include/asm/mte.h (limited to 'arch/arm64/include/asm/mte.h') diff --git a/arch/arm64/include/asm/mte.h b/arch/arm64/include/asm/mte.h new file mode 100644 index 0000000000..4cedbaa16f --- /dev/null +++ b/arch/arm64/include/asm/mte.h @@ -0,0 +1,219 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2020 ARM Ltd. + */ +#ifndef __ASM_MTE_H +#define __ASM_MTE_H + +#include +#include + +#ifndef __ASSEMBLY__ + +#include +#include +#include +#include +#include + +#include + +void mte_clear_page_tags(void *addr); +unsigned long mte_copy_tags_from_user(void *to, const void __user *from, + unsigned long n); +unsigned long mte_copy_tags_to_user(void __user *to, void *from, + unsigned long n); +int mte_save_tags(struct page *page); +void mte_save_page_tags(const void *page_addr, void *tag_storage); +void mte_restore_tags(swp_entry_t entry, struct page *page); +void mte_restore_page_tags(void *page_addr, const void *tag_storage); +void mte_invalidate_tags(int type, pgoff_t offset); +void mte_invalidate_tags_area(int type); +void *mte_allocate_tag_storage(void); +void mte_free_tag_storage(char *storage); + +#ifdef CONFIG_ARM64_MTE + +/* track which pages have valid allocation tags */ +#define PG_mte_tagged PG_arch_2 +/* simple lock to avoid multiple threads tagging the same page */ +#define PG_mte_lock PG_arch_3 + +static inline void set_page_mte_tagged(struct page *page) +{ + /* + * Ensure that the tags written prior to this function are visible + * before the page flags update. + */ + smp_wmb(); + set_bit(PG_mte_tagged, &page->flags); +} + +static inline bool page_mte_tagged(struct page *page) +{ + bool ret = test_bit(PG_mte_tagged, &page->flags); + + /* + * If the page is tagged, ensure ordering with a likely subsequent + * read of the tags. + */ + if (ret) + smp_rmb(); + return ret; +} + +/* + * Lock the page for tagging and return 'true' if the page can be tagged, + * 'false' if already tagged. PG_mte_tagged is never cleared and therefore the + * locking only happens once for page initialisation. + * + * The page MTE lock state: + * + * Locked: PG_mte_lock && !PG_mte_tagged + * Unlocked: !PG_mte_lock || PG_mte_tagged + * + * Acquire semantics only if the page is tagged (returning 'false'). + */ +static inline bool try_page_mte_tagging(struct page *page) +{ + if (!test_and_set_bit(PG_mte_lock, &page->flags)) + return true; + + /* + * The tags are either being initialised or may have been initialised + * already. Check if the PG_mte_tagged flag has been set or wait + * otherwise. + */ + smp_cond_load_acquire(&page->flags, VAL & (1UL << PG_mte_tagged)); + + return false; +} + +void mte_zero_clear_page_tags(void *addr); +void mte_sync_tags(pte_t pte); +void mte_copy_page_tags(void *kto, const void *kfrom); +void mte_thread_init_user(void); +void mte_thread_switch(struct task_struct *next); +void mte_cpu_setup(void); +void mte_suspend_enter(void); +void mte_suspend_exit(void); +long set_mte_ctrl(struct task_struct *task, unsigned long arg); +long get_mte_ctrl(struct task_struct *task); +int mte_ptrace_copy_tags(struct task_struct *child, long request, + unsigned long addr, unsigned long data); +size_t mte_probe_user_range(const char __user *uaddr, size_t size); + +#else /* CONFIG_ARM64_MTE */ + +/* unused if !CONFIG_ARM64_MTE, silence the compiler */ +#define PG_mte_tagged 0 + +static inline void set_page_mte_tagged(struct page *page) +{ +} +static inline bool page_mte_tagged(struct page *page) +{ + return false; +} +static inline bool try_page_mte_tagging(struct page *page) +{ + return false; +} +static inline void mte_zero_clear_page_tags(void *addr) +{ +} +static inline void mte_sync_tags(pte_t pte) +{ +} +static inline void mte_copy_page_tags(void *kto, const void *kfrom) +{ +} +static inline void mte_thread_init_user(void) +{ +} +static inline void mte_thread_switch(struct task_struct *next) +{ +} +static inline void mte_suspend_enter(void) +{ +} +static inline void mte_suspend_exit(void) +{ +} +static inline long set_mte_ctrl(struct task_struct *task, unsigned long arg) +{ + return 0; +} +static inline long get_mte_ctrl(struct task_struct *task) +{ + return 0; +} +static inline int mte_ptrace_copy_tags(struct task_struct *child, + long request, unsigned long addr, + unsigned long data) +{ + return -EIO; +} + +#endif /* CONFIG_ARM64_MTE */ + +static inline void mte_disable_tco_entry(struct task_struct *task) +{ + if (!system_supports_mte()) + return; + + /* + * Re-enable tag checking (TCO set on exception entry). This is only + * necessary if MTE is enabled in either the kernel or the userspace + * task in synchronous or asymmetric mode (SCTLR_EL1.TCF0 bit 0 is set + * for both). With MTE disabled in the kernel and disabled or + * asynchronous in userspace, tag check faults (including in uaccesses) + * are not reported, therefore there is no need to re-enable checking. + * This is beneficial on microarchitectures where re-enabling TCO is + * expensive. + */ + if (kasan_hw_tags_enabled() || + (task->thread.sctlr_user & (1UL << SCTLR_EL1_TCF0_SHIFT))) + asm volatile(SET_PSTATE_TCO(0)); +} + +#ifdef CONFIG_KASAN_HW_TAGS +void mte_check_tfsr_el1(void); + +static inline void mte_check_tfsr_entry(void) +{ + if (!system_supports_mte()) + return; + + mte_check_tfsr_el1(); +} + +static inline void mte_check_tfsr_exit(void) +{ + if (!system_supports_mte()) + return; + + /* + * The asynchronous faults are sync'ed automatically with + * TFSR_EL1 on kernel entry but for exit an explicit dsb() + * is required. + */ + dsb(nsh); + isb(); + + mte_check_tfsr_el1(); +} +#else +static inline void mte_check_tfsr_el1(void) +{ +} +static inline void mte_check_tfsr_entry(void) +{ +} +static inline void mte_check_tfsr_exit(void) +{ +} +#endif /* CONFIG_KASAN_HW_TAGS */ + +#endif /* __ASSEMBLY__ */ +#endif /* __ASM_MTE_H */ -- cgit v1.2.3